Krebs on Security

In-depth security news and investigation

Posts Tagged: firefox

Popular file-sharing site Mega.nz is warning users that cybercriminals hacked its browser extension for Google Chrome so that usernames and passwords submitted through the browser were copied and forwarded to a rogue server in Ukraine. This attack serves as a fresh reminder that legitimate browser extensions can and periodically do fall into the wrong hands, and that it makes good security sense to limit your exposure to such attacks by getting rid of extensions that are no longer useful or actively maintained by developers.

“On 4 September 2018 at 14:30 UTC, an unknown attacker uploaded a trojaned version of MEGA’s Chrome extension, version 3.39.4, to the Google Chrome webstore. Upon installation or autoupdate, it would ask for elevated permissions (Read and change all your data on the websites you visit) that MEGA’s real extension does not require and would (if permissions were granted) exfiltrate credentials for sites including amazon.com, live.com, github.com, google.com (for webstore login), myetherwallet.com, mymonero.com, idex.market and HTTP POST requests to other sites, to a server located in Ukraine. Note that mega.nz credentials were not being exfiltrated.”

Browser extensions can be incredibly handy and useful, but compromised extensions — depending on the level of “permissions” or access originally granted to them — also can give attackers access to all data on your computer and the Web sites you visit.

For its part, Google tries to communicate the potential risk of extensions using three “alert” levels: Low, medium and high, as detailed in the screenshot below. In practice, however, most extensions carry the medium or high alert level, which means that if the extension is somehow compromised (or malicious from the get-go), the attacker in control of it is going to have access to ton of sensitive information on a great many Internet users. Continue reading →

Google has not had any of its 85,000+ employees successfully phished on their work-related accounts since early 2017, when it began requiring all employees to use physical Security Keys in place of passwords and one-time codes, the company told KrebsOnSecurity.

A YubiKey Security Key made by Yubico. The basic model featured here retails for $20.

Security Keys are inexpensive USB-based devices that offer an alternative approach to two-factor authentication (2FA), which requires the user to log in to a Web site using something they know (the password) and something they have (e.g., a mobile device).

A Google spokesperson said Security Keys now form the basis of all account access at Google.

“We have had no reported or confirmed account takeovers since implementing security keys at Google,” the spokesperson said. “Users might be asked to authenticate using their security key for many different apps/reasons. It all depends on the sensitivity of the app and the risk of the user at that point in time.”

The basic idea behind two-factor authentication is that even if thieves manage to phish or steal your password, they still cannot log in to your account unless they also hack or possess that second factor.

The most common forms of 2FA require the user to supplement a password with a one-time code sent to their mobile device via text message or an app. Indeed, prior to 2017 Google employees also relied on one-time codes generated by a mobile app — Google Authenticator.

In contrast, a Security Key implements a form of multi-factor authentication known as Universal 2nd Factor (U2F), which allows the user to complete the login process simply by inserting the USB device and pressing a button on the device. The key works without the need for any special software drivers.

Once a device is enrolled for a specific Web site that supports Security Keys, the user no longer needs to enter their password at that site (unless they try to access the same account from a different device, in which case it will ask the user to insert their key).

U2F is an emerging open source authentication standard, and as such only a handful of high-profile sites currently support it, including Dropbox, Facebook, Github (and of course Google’s various services). Most major password managers also now support U2F, including Dashlane, and Keepass.Duo Security [full disclosure: an advertiser on this site] also can be set up to work with U2F.

Currently, U2F is supported by Chrome, Mozilla Firefox, and Opera. In both Firefox and Quantum (the newer, faster version of Firefox), U2F is not enabled by default. To turn it on, type “about:config” in the browser bar, type or paste “security.webauth.u2f” and double-click the resulting entry to change the preference’s value from “false” to “true.”

Microsoft says it expects to roll out updates to its flagship Edge browser to support U2F later this year. According to a recent article at 9to5Mac.com, Apple has not yet said when or if it will support the standard in its Safari browser. Continue reading →

Adobe has pushed out a critical update to plug at least 52 security holes in its widely-used Flash Player browser plugin, and another update to patch holes in Adobe Reader. Separately, Microsoft released 11 security updates to fix vulnerabilities more than 40 flaws in Windows and related software.

First off, if you have Adobe Flash Player installed and haven’t yet hobbled this insecure program so that it runs only when you want it to, you are playing with fire. It’s bad enough that hackers are constantly finding and exploiting zero-day flaws in Flash Player before Adobe even knows about the bugs.

The bigger issue is that Flash is an extremely powerful program that runs inside the browser, which means users can compromise their computer just by browsing to a hacked or malicious site that targets unpatched Flash flaws.

The smartest option is probably to ditch this insecure program once and for all and significantly increase the security of your system in the process. I’ve got more on that approach — as well as slightly less radical solutions — in A Month Without Adobe Flash Player.

If you choose to update, please do it today. The most recent versions of Flash should be available from this Flash distribution page or the Flash home page. Windows users who browse the Web with anything other than Internet Explorer may need to apply this patch twice, once with IE and again using the alternative browser (Firefox, Opera, e.g.). Chrome and IE should auto-install the latest Flash version on browser restart.

Happily, Adobe has delayed plans to stop distributing direct download links to its Flash Player program. The company had said it would decommission the direct download page on June 30, 2016, but the latest, patched Flash version 22.0.0.209 for Windows and Mac systems is still available there. The wording on the site has been changed to indicate the download links will be decommissioned “soon.” Continue reading →

Adobe and Microsoft today each released software updates to fix serious security flaws in their products. Adobe pushed an update that plugs a pair of holes in its Flash Player software. Microsoft issued five updates, including one that addresses a zero-day vulnerability in Internet Explorer that attackers have been exploiting of late.

Microsoft’s five bulletins address 23 distinct security weaknesses in Microsoft Windows, Internet Explorer and Silverlight. The Internet Explorer patch is rated critical for virtually all supported versions of IE, and plugs at least 18 security holes, including a severe weakness in IE 9 and 10 that is already being exploited in targeted attacks.

Microsoft notes that the exploits targeting the IE bug seen so far appear to perform a check for the presence of Microsoft’s Enhanced Mitigation Experience Toolkit (EMET); according to Microsoft, the exploits fail to proceed if EMET is detected. I’ve recommended EMET on several occasions, and would encourage any Windows users who haven’t yet deployed this tool to spend a few minutes reading this post and consider taking advantage of it to further harden their systems. The latest version — 4.1 — is available at this link and requires Microsoft’s .NET Framework 4 platform. For those of you who don’t mind beta-testing software, Microsoft has released a preview version of the next generation of EMET — EMET 5.0 Technical Preview.

This month’s updates include a fix for another dangerous bug — deep within the operating system on just about every major version of Windows — that also was publicly disclosed prior to today’s patches. Microsoft’s Technet Blog has more details on these and other bulletins released today.

The second Tuesday of the month is upon us, and that means it’s once again time to get your patches on, people (at least for readers running Windows or Adobe products). Microsoft today pushed out nine patch bundles to plug security holes in Windows and its other products. Separately, Adobe issued updates for its Flash and Shockwave media players that address four distinct security holes in each program.

Microsoft called special attention to a cumulative update for Internet Explorer that fixes two critical vulnerabilities present in virtually every version of IE ever produced, including IE 9, 10 and IE on Windows RT, the operating system for mobile devices and tablets.

Adobe’s update brings Adobe Flash Player to v. 11.7.700.169 on Windows and Mac devices (the latest version numbers for other operating systems are listed in the chart below). Internet Explorer 10 and Google Chrome should automatically update to the latest version. Google has already pushed out the Flash update with Chrome v. 26.0.1410.63 for Mac and Linux, and v. 26.0.1410.64 for Windows; if your Chrome version isn’t at the latest (you can check which version by clicking the customize tab to the right of the address bar and then “About Google Chrome’), try closing and restarting the browser. Continue reading →

Adobe has released an emergency update for its Flash Player software that fixes three critical vulnerabilities, two of which the company warns are actively being exploited to compromise systems.

In an advisory, Adobe said two of the bugs quashed in this update (CVE-2013-0643 and CVE-2013-0648) are being used by attackers to target Firefox users. The company noted that the attacks are designed to trick users into clicking a link which redirects to a Web site serving malicious Flash content.

Readers can be forgiven for feeling patch fatigue with Flash: This is the third security update that Adobe has shipped for Flash in the last month. On Feb. 12, Adobe released a patch to plug at least 17 security holes in Flash. On Feb. 7, Adobe rushed out an update to fix two other flaws that attackers were already exploiting to break into vulnerable computers.

Adobe and Microsoft each have issued security updates to fix multiple critical vulnerabilities in their products. Adobe released updates for Flash Player, AIR and Shockwave; Microsoft pushed out a dozen patches addressing at least 57 security holes in Windows, Office, Internet Explorer, Exchange and .NET Framework.

Five of the 12 patches Microsoft released today earned its most dire “critical” label, meaning these updates fix vulnerabilities that attackers or malware could exploit to seize complete control over a PC with no help from users.

Thirteen of the 57 bugs squashed in Microsoft’s patch batch address issues with Internet Explorer; other critical patches fix problems in the Windows implementation of Vector Markup Language (VML), Microsoft Exchange, and flaws in the way Windows handles certain media files. The remaining critical patch fixes a flaw that is present only on Windows XP systems.

Updates are available via Windows Update or from Automatic Update. A note about applying these Windows patches: Today’s batch includes an update for .NET, which in my experience should be applied separately. In nearly every case where I’ve experienced problems updating Windows, a huge .NET patch somehow gummed up the works. Consider applying the rest of the patches first, rebooting, and then installing the .NET update, if your system requires it.

And for the second time in a week, Adobe has released an update for its Flash Player software. This one addresses at least 17 distinct vulnerabilities; unlike last week’s emergency Flash Update, this one thankfully doesn’t address flaws that are already actively being exploited, according to Adobe. Check the graphic below for the most recent version that includes the updates relevant to your operating system. This link should tell you which version of Flash your browser has installed. The most recent versions are available from the Adobe download center, but beware potentially unwanted add-ons, like McAfee Security Scan). To avoid this, uncheck the pre-checked box before downloading, or grab your OS-specific Flash download from here.

On Thursday, the world learned that attackers were breaking into computers using a previously undocumented security hole in Java, a program that is installed on hundreds of millions of computers worldwide. This post aims to answer some of the most frequently asked questions about the vulnerability, and to outline simple steps that users can take to protect themselves.

Update, Jan. 13, 8:14 p.m. ET: Oracle just released a patch to fix this vulnerability. Read more here.

Q: What is Java, anyway?
A: Java is a programming language and computing platform that powers programs including utilities, games, and business applications. According to Java maker Oracle Corp., Java runs on more than 850 million personal computers worldwide, and on billions of devices worldwide, including mobile and TV devices. It is required by some Web sites that use it to run interactive games and applications.

Q: So what is all the fuss about?
A: Researchers have discovered that cybercrooks are attacking a previously unknown security hole in Java 7 that can be used to seize control over a computer if a user visits a compromised or malicious Web site.

Q: Yikes. How do I protect my computer?
A: The version of Java that runs on most consumer PCs includes a browser plug-in. According to researchers at Carnegie Mellon University‘s CERT, unplugging the Java plugin from the browser essentially prevents exploitation of the vulnerability. Not long ago, disconnecting Java from the browser was not straightforward, but with the release of the latest version of Java 7 — Update 10 — Oracle included a very simple method for removing Java from the browser. You can find their instructions for doing this here.

Q: How do I know if I have Java installed, and if so, which version?
A: The simplest way is to visit this link and click the “Do I have Java” link, just below the big red “Download Java” button.

Q: I’m using Java 6. Does that mean I don’t have to worry about this?
A: There have been conflicting findings on this front. The description of this bug at the National Vulnerability Database (NVD), for example, states that the vulnerability is present in Java versions going back several years, including version 4 and 5. Analysts at vulnerability research firm Immunity say the bug could impact Java 6 and possibly earlier versions. But Will Dormann, a security expert who’s been examining this flaw closely for CERT, said the NVD’s advisory is incorrect: CERT maintains that this vulnerability stems from a component that Oracle introduced with Java 7. Dormann points to a detailed technical analysis of the Java flaw by Adam Gowdiak of Security Explorations, a security research team that has alerted Java maker Oracle about a large number of flaws in Java. Gowdiak says Oracle tried to fix this particular flaw in a previous update but failed to address it completely.

Either way, it’s important not to get too hung up on which versions are affected, as this could become a moving target. Also, a new zero-day flaw is discovered in Java several times a year. That’s why I’ve urged readers to either uninstall Java completely or unplug it from the browser no matter what version you’re using.

Q: A site I use often requires the Java plugin to be enabled. What should I do?
A: You could downgrade to Java 6, but that is not a very good solution. Oracle will stop supporting Java 6 at the end of February 2013, and will soon be transitioning Java 6 users to Java 7 anyway. If you need Java for specific Web sites, a better solution is to adopt a two-browser approach. If you normally browse the Web with Firefox, for example, consider disabling the Java plugin in Firefox, and then using an alternative browser (Chrome, IE9, Safari, etc.) with Java enabled to browse only the site(s) that require(s) it.

Q: I am using a Mac, so I should be okay, right?
A: Not exactly. Experts have found that this flaw in Java 7 can be exploited to foist malware on Mac and Linux systems, in addition to Microsoft Windows machines. Java is made to run programs across multiple platforms, which makes it especially dangerous when new flaws in it are discovered. For instance, the Flashback worm that infected more than 600,000 Macs wiggled into OS X systems via a Java flaw. Oracle’s instructions include advice on how to unplug Java from Safari. I should note that Apple has not provided a version of Java for OS X beyond 6, but users can still download and install Java 7 on Mac systems. However, it appears that in response to this threat, Apple has taken steps to block Java from running on OS X systems.

Q: I don’t browse random sites or visit dodgy porn sites, so I shouldn’t have to worry about this, correct?
A: Wrong. This vulnerability is mainly being exploited by exploit packs, which are crimeware tools made to be stitched into Web sites so that when visitors come to the site with vulnerable/outdated browser plugins (like this Java bug), the site can silently install malware on the visitor’s PC. Exploit packs can be just as easily stitched into porn sites as they can be inserted into legitimate, hacked Web sites. All it takes is for the attackers to be able to insert one line of code into a compromised Web site.

Q: I’ve read in several places that this is the first time that the U.S. government has urged computer users to remove or wholesale avoid using a particular piece of software because of a widespread threat. Is this true?
A: Not really. During previous high-alert situations, CERT has advised Windows users to avoid using Internet Explorer. In this case, CERT is not really recommending that users uninstall Java: just that users unplug Java from their Web browser.

Adobe and Microsoft today separately issued updates to fix critical security vulnerabilities in their products. Adobe pushed out fixes for security issues in Acrobat, Adobe Reader and its Flash Player plugin. Microsoft released seven patches addressing at least a dozen security holes in Windows and other software, although it failed to issue an official patch for a dangerous flaw in its Internet Explorer Web browser that attackers are now actively exploiting.

Two of the patches that Microsoft issued today earned a “critical” rating, signifying that these vulnerabilities could be exploited to fully compromise vulnerable Windows systems without any help from users. Microsoft called special attention to two critical bugs in its XML Core Services component; the company said it is likely that malware or miscreants will figure out a way to exploit these flaws in active attacks sometime within the next 30 days.

Unfortunately, Microsoft did not offer an official fix for a critical Windows flaw that malware and miscreants are already exploiting. In late December, Microsoft acknowledged that attackers were using a previously undocumented security hole in Internet Explorer versions 6 through 8 to break into Windows PCs. Microsoft later issued a stopgap “FixIt” tool to help lessen the vulnerability on affected systems, but researchers last week demonstrated that the FixIt tool only blocked some methods of attacking the flaw, leaving other ways unguarded. Meanwhile, a working copy of the exploit has been folded into Metasploit, a free penetration testing tool.

“Microsoft is not providing a patch today, though they have provided a Fix-It for the issue,” Kandek wrote in a blog post. “The vulnerability should be tracked closely, as a large percentage of enterprises still run the affected versions.”

Users who wish to continue browsing the Web with IE should upgrade to IE9 if possible (IE10 on Windows 8 also is not vulnerable). Users still on Windows XP will not be able to update to IE9, but may be able to derive some protection from the FixIt tool and by using Microsoft’s EMET tool. XP users may be better off, however, browsing with Firefox or Chrome with some type of script blocking and/or sandbox in place. More information on how to use EMET and script blocking options is available in my Tools for a Safer PC primer. More details about today’s updates from Microsoft can be found at the Microsoft Security Response Center blog and in the security bulletin summaries for each patch.

The Adobe Flash patch fixes at least one critical vulnerability in the media player plugin. Updates are available for all supported versions of Flash, including for Windows, Mac, Linux and Android. See the chart below for the latest version number broken down by operating system.

Microsoft is urging Windows users who browse the Web with Internet Explorer to use a free tool called EMET to block attacks against a newly-discovered and unpatched critical security hole in IE versions 7, 8 and 9. But some experts say that advice falls short, and that users can better protect themselves by surfing with an alternative browser until Microsoft issues a proper patch for the vulnerability.

The application page of EMET.

EMET, short for the Enhanced Mitigation Experience Toolkit, is a tool that can help Windows users beef up the security of commonly used applications, whether they are made by a third-party vendor or by Microsoft. EMET allows users to force applications to use one or both of two key security defenses built into Windows Vista and Windows 7 — Address Space Layout Randomization (ASLR) and Data Execution Prevention (DEP).

Put very simply, DEP is designed to make it harder to exploit security vulnerabilities on Windows, and ASLR makes it more difficult for exploits and malware to find the specific places in a system’s memory that they need to do their dirty work.

Before I get into the how-tos on EMET, a few caveats. EMET is a great layer of security that Windows users can and should use to enhance the security of applications. But EMET may not block the exploit code now publicly available through the Metasploit framework. In fact, Tod Beardlsey, an engineering manager with Rapid7, the security firm that manages Metasploit, told The Associated Press that EMET does not appear to be completely effective against this exploit.

I asked Metasploit founder HD Moore what he thought was the best way to block this exploit, and he pointed out that the exploit available through Metasploit requires the presence of Java on the host machine in order to execute properlyon IE 8/9 on Windows 7 and Vista systems (the exploit works fine without Java against IE7 on XP/Vista and IE8 on XP). Obviously, while the lack of Java on a Windows machine may not prevent other exploits against this flaw, it is a great first start. I have consistently urged computer users of all stripes to uninstall Java if they have no specific use for it.